Thanks again for the replies. I looked in the DAC comparison charts and various threads on this forum and I just ordered a Topping D90.
I chose it over the Modius because the D90 has more of the features I want, e.g. up to 24/768 (matching with my Mojo); DSD and Bluetooth. I didn't go for the MQA version. It's my first audio product from an actual Chinese manufacturer (as opposed to lots of things which I own which from companies elsewhere and made in China) so fingers crossed I have no major issues (I bought from Audiophonics in France so that should help in relation to EU consumer protection laws).
I also considered the SMSL M400 which I saw has very slightly better measurements than the D90 and a presence on this forum (which is great) but decided not to get it because of its inferior build quality.
I was also interested in the Gustard DAC-A22 which has two (rather than one) AK4499 DACs inside and is even better built than the D90 but then I read the thread on here which indicated that the implementation sadly seems flawed. Gustard also seem to have no official English presence on the Internet - not even a website!
I was on the verge of ordering a Chord Qutest (£1,075 after a 10% discount which I found a UK dealer offering) until I came across this thread yesterday and asked for your advice. I've now ended up with a better, more fully featured and (hopefully) trouble free DAC for around 40% less! Well worth the donation I made yesterday to this site.
Thanks again to everyone and I look forward to reading more and maybe contributing if I have anything to say!